Studies were continued in several areas related to the biochemistry and genetic regulation of membrane components. A glycoprotein of approx. 30,000 m.w., associated with the plasma membrane of B lymphocytes (human) was further characterized. The expression of Ig was studied in cultured lymphoblastoid lines which produced multiple heavy chains. Hybrid cells from parental mouse hepatoma and human lymphoid cells were produced to be analyzed for regulation of various proteins. Studies on the synthesis and secretion of human alpha-1-antitrypsin in vitro were initiated. Further characterization of the "cystic fibrosis" factor and its relationship to complement components was continued.